add win32 (msvc) support

core/sys/windows/bitop.c

@@ -0,0 +1,54 @@
+#include <blue/core/bitop.h>
+#include <intrin.h>
+#include <assert.h>
+
+#define CPU_FEATURE_YES		1
+#define CPU_FEATURE_NO		-1
+#define CPU_FEATURE_UNKNOWN	0
+
+static int cpu_supports_popcnt = CPU_FEATURE_UNKNOWN;
+
+static int check_popcnt_support()
+{
+	int d[4];
+	__cpuid(d, 0x00000001);
+
+	return (d[2] & 0x800000) ? CPU_FEATURE_YES : CPU_FEATURE_NO;
+}
+
+int b_popcountl(long v)
+{
+	if (cpu_supports_popcnt == CPU_FEATURE_UNKNOWN) {
+		cpu_supports_popcnt = check_popcnt_support();
+	}
+
+	if (cpu_supports_popcnt == CPU_FEATURE_YES) {
+		return __popcnt64(v);
+	}
+	
+	assert(0 && "CPU does not support popcount!");
+	return 0;
+}
+
+int b_ctzl(long v)
+{
+	unsigned long trailing_zero = 0;
+
+	if (_BitScanForward64(&trailing_zero, v)) {
+		return trailing_zero;
+	} else {
+		return 64;
+	}
+}
+
+int b_clzl(long v)
+{
+	unsigned long leading_zero = 0;
+
+	if (_BitScanReverse64(&leading_zero, v)) {
+		return 64 - leading_zero;
+	} else {
+		// Same remarks as above
+		return 64;
+	}
+}